Clang: Update symbol database if file has changed

The code in the symbol indexer is quite similar, but still different
enough to prevent easy reuse of the function.

Change-Id: I47907d90066da922eafe8ff3cce124ea47ea4a0a
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>

src/tools/clangrefactoringbackend/source/clangrefactoringbackend-source.pri

@@ -17,7 +17,8 @@ HEADERS += \
     $$PWD/symbolsvisitorbase.h \
     $$PWD/usedmacro.h \
     $$PWD/sourcedependency.h \
-    $$PWD/filestatus.h
+    $$PWD/filestatus.h \
+    $$PWD/projectpartartefacts.h
 
 !isEmpty(LIBTOOLING_LIBS) {
 SOURCES += \